Almost everyone can recall the rite of passage of earning a driver’s license. Driving is a part of our independence, and many of us enjoy getting behind the wheel to explore the beautiful state around us, or just getting out of the house. For some, the ability to meet friends is the highlight of the week. We love our cars. Unfortunately, certain conditions may rob us of the ability to safely operate a motor vehicle. Parkinson disease (PD) is one such condition that may cause people to have to hand over the keys.
Knowing when to give up driving is sometimes difficult, and can be a source of great tension among patients, family members, and doctors. Remember, it’s all about safety for you and everyone else on the road. Many experts have tried to figure out the best way to go about this. One study of risk factors (1) emphasizes several relevant issues:
- caregiver reports of marginal or unsafe skills
- history of citations
- history of crashes
- driving <60 miles per week
- avoiding certain situations such as high traffic areas
- aggression
- impulsivity
- Mini-Mental Status Examination (MMSE) score ≤24
Other confounding issues include alcohol, medications, sleep disorders, visual impairment, and motor impairment of PD. These are all factors I consider when meeting with a patient.
Other authors have shown that driving is simply impaired in PD compared with healthy comparison drivers, due to underlying motor, cognitive, and visual impairments that can affect fitness to drive (2). There are many articles on this topic.
It would seem intuitive that as long as disease is mild, driving ability would probably be fine.
However, critical abilities for driving include visual attention, spatial awareness, and executive skills not measured by the standard Unified Parkinson’s Disease Rating Scale (UPDRS) motor score, or the Hoehn and Yahr scale. Disease duration is not a good predictor, either.
Driving requires executive function. In particular, mental flexibility in the process of updating the information in working memory may often be affected in PD (3). This might seem slightly complicated. To explain, working memory is temporary mental storage needed to carry out a complex task or mental processing. Updating can be thought of as refreshing the working memory. For example, you might need to update road sign information, or conditions of the road. Patients must also have mental flexibility and quick reaction time, which can be diminished in PD, in order to adapt to rapidly changing circumstances, such as when someone unexpectedly pulls in front of you or “cuts you off.”
Whether or not one can continue driving is a difficult discussion, and one I have almost daily with patients and their families. Even for those who can continue driving, I would recommend taking at least these steps to be safe:
- Do not drive distracted. Turn off the radio and cell phone, and put down the food and drinks. Wait until you have parked for the conversations.
- Do not drive when you are tired, fatigued, or have medication issues that would make you less safe, such as dyskinesia, “wearing off,” or sleepiness. If you are prone to sleep attacks, a rare side effect of dopamine agonists, do not drive until a change in medications has resolved that problem altogether.
- Do not drive at night if your vision is poor in low light.
- Do not drive unfamiliar, busy roads.
- Do not drive with poor posture. Sit up straight, and make sure you are able turn your head to look behind you before hitting the road.
Some patients may just need to revisit driving skills.
The Southern Maine Agency on Aging has a list of driver evaluation and assessment resources, driver improvement courses, and older driver safety information available online at http://www.smaaa.org/documents/cs/fcg/DrivingInternetTools.pdf
Warning signs that you or a loved one might be an unsafe driver:
- Driving too slowly
- Getting lost on a familiar route
- Ignoring traffic signs
- Difficulty with turns or changing lanes
- Drifting into other traffic lanes, or driving on the center line between two lanes
- Driving on the wrong side of the road
- Signaling incorrectly, or not at all
- Inattention to other vehicles, pedestrians, and road hazards
Parking inappropriately- Hitting parked cars or buildings when trying to park or back up
- Tickets, traffic violations
- Near-misses and accidents
The State of Maine has rules regarding driving with PD, most recently updated December 31, 2016. The Secretary of State and Bureau of Motor Vehicles repealed and replaced Chapter 3: Physical and Mental Competence to Operate a Motor Vehicle. Doctors across the state were provided with a copy of the new rules, the “Functional Ability Profiles” booklet. These rules are also available online at https://www1.maine.gov/sos/bmv/licenses/medical.html
If you have Parkinson disease or a related parkinsonian condition, you are obliged by the state to declare yourself to the Bureau of Motor Vehicles, or to ask your doctor to fill out an FAP form. The physician will have to designate you as one of three profile levels:
Level 1: No diagnosed condition, no known disorder. This usually comes up when a patient has been misdiagnosed, or made a mistake in paperwork.
No driving test required
Level 2: Condition fully recovered. This might include drug-induced parkinsonism, considered recovered when symptoms resolve after the causative medication is stopped.
No driving test required
Level 3: This is active impairment and is divided into mild, moderate, and severe categories:
Mild
- physical symptoms that do not pose a risk for safe operation of a vehicle
- no cognitive or psychiatric symptoms
- none of the medications taken cause drowsiness
Driving test required every 2 years
Moderate
- physical symptoms and/or side effects of medication that may potentially interfere with the safe operation of a vehicle
- may have early cognitive or psychiatric symptoms
Driving test required every year
Severe
- physical symptoms or side effects of medications that are incompatible with safe operation of a motor vehicle
No driving
REFERENCES
- Zesiewiczet al. Driving safety in Parkinson’s disease. Neurology. 2002 Dec 10;59(11):1787-8.
- Crizzle et al. Parkinson disease and driving: An evidence-based review. Neurology. 2012;79;2067-2074.
- Ranchet et al. Impaired updating ability in drivers with Parkinson’s disease. J Neurol Neurosurg Psychiatry. 2011;82:218e223.
